Experiments on the replication of herpes simplex virus (HSV) are being carried out. We are using low temperature hybridization in non-aqueous solvents for the isolation and characterization of specific HSV mRNA sequences. These techniques in conjunction with electron microscopic looalization of HSV specific mRNA on the viral genome are being used to functionally map the HSV genome. BIBLIOGRAPHIC REFERENCES: Rice, M., Stringer, J., Swanstrom, R., and Wagner, E. The Association of the Infecting DNA of Herpes Simplex Virus with Cellular Components. Virology 70, 185-189 (1976). Wagner, E., Swanstrom, R., Rice, M., Howell, L., and Love, J. Variation in the Molecular Size of the DNA from Closely Related Strains of Type 1 HSV. Biochem. Biophys. Acta 435, 192-205 (1976).